There are known numerous devices for the geometric inspection of vehicles, in which a measuring head provided with suitable detectors is secured to a wheel rim of the vehicle and transmits by wire connection or wireless connection signals representative of physical parameters, to a programmable central unit, adapted to compute the geometry of the vehicle.
However, these known measuring heads comprise detectors that are fragile and electronic members sensitive to shocks, giving rise to risk of damage during operations of geometric inspection, particularly during securement on the wheel rim or during mounting of the wheel rim.
To overcome this drawback, it has been provided to secure targets or mirrors on the wheel rims of vehicles, so as to illuminate these targets or these mirrors and to observe the reflected image by means of a camera or like observation member. A portable apparatus for measuring axes by laser of this type is described in the document "KRAFTHAND", volume 9, May 5, 1979, page 608. Another apparatus of this type is described in WO 94/05969.
These apparatus with fixed target or mirror on wheel rims have the drawback of requiring a device for image analysis and a relatively complicated computation to determine the angle of sight relative to the image in perspective or in reflection observed with the image in real size of each target or of each member. Moreover, because of the distance from the observation bench to the targets or mirrors, the selectivity of measurement is low, which requires the use of detectors of high precision or matrix observation cameras with high resolution.